DC-targeted down-regulation of MRP4 reduced human skin DC migration. GM-CSF– and IL-4–activated human skin DCs were in situ (intradermally) targeted with adenoviruses encoding shMRP4 or shMRP1, using a sCAR-CD40L fusion protein (CFm40L) and a human skin explant culture model. After 48 hours, migrated DCs were harvested and quantified (n = 4 donors, 12-20 biopsies per condition per experiment; mean ± SD).